The flag is part of the active operation counting, which is utilized in load balancing. The active operation count per backend is used by default as criteria when router chooses to which backend a query should be routed.
All prepare commands are executed in every backend server currently connected.
All executes are routed to master. If stmt type was recorded in prepare phase in rwsplit router, read-only stmts could be routed to slaves.
COM_STMT_PREPARE gets arbitrary number of response packets from backend database. Since statements are prepared in every backend server and only one multi-packet response can be replied to client, redundant multi-packet responses are discarded. This is done in router. Mechanisms from session command handling are utilized with little changes: router must identify when response consists of multiple packets so that it knows to calculate the number of packets in response and that it is able to discard correct number of packets.
Information to the reply-handling router is provided by backend protocol, which includes a ordered list of commands of commands sent to protocol-owning backend server. A command is stored to protocol struct in mysql_backend.c:gw_MySQLWrite_backend if the statement buffer's type has GWBUF_TYPE_SINGLE_STMT set in mysql_client.c:route_by_statement. GWBUF_TYPE_SINGLE_STATEMENT indicates that there is single statement in the buffer, as opposite to Read Connection router, which accepts streaming input from client.
Conflicts:
server/core/session.c
server/modules/protocol/mysql_backend.c
server/modules/routing/readwritesplit/readwritesplit.c
Resolved.
Addition of user in topfilter report and general tidyup
Rwsplit handles ERRACT_NEW_CONNECTION by clearing backend reference, removing callbacks and associating backend reference with new backend server. If it succeeds and the router session can continue, handleError returns true. Otherwise false. When ever false is returned it means that session must be closed.
Rwsplit now tolerates backend failures in a way that it searches new backends when monitor, backend, or client operation fails due to backend failure.
Added flags to those backend references which have sent something to backend which causes the backend to send results or reply back. Didn't add removal of the flag since there's currently no way to tell whether response from backend contains anything else than session command reply - which aren't counted when BREF_WAITING_RESULT is set and cleared.
dcb.h: define ERRHAND temporarily since changes are still behind that macro
Defined two error handling actions in router.h: ERRACT_NEW_COMMECTION and ERRACT_REPLY_CLIENT.
Failed database is logged at expanding frequence to error and to message log due changes in mysql_mon.c. Added two new members in MONITOR_SERVERS: mon_err_count, and mon_prev_status so that each backend can be treated individually.
Error handling: if mysql_backend.c:dcb_read fails, router's handleError is called instead of closing session.
If mysql_client.c:SESSION_ROUTE_QUERY fails router's handleError is called instead of sending error to client.
readwritesplit.c:select_connect_backend_servers is modified so that in can be called during active router session. When called, it attempts to find one master and maximum number of configured slaves in correct state if necessary.
When handleError needs to replace failed unit it now calls select_connect_backend_servers.
Added a lot of logging to error, trace and message logs which should help the user to handle errors which can't be automatically resolved, like attempt to use nonexisting database.
monitors used mysql_ping without MYSQL_OPT_READ_TIMEOUT which caused read to block. Fixed in mysql and galera monitor.
Added log writing per each status change of each server and repeatedly if server is not running.
Removed SERVER_IS_JOINED checks from rwsplit router.
be extracted from the modules.
This gives a way to verify the API that the module provides as well
as the version of that API. The hope is that this will make it possible
for MaxScale to detect out of date plugins and either adapt to use them
or reject loading them.
Also added the ability to set a release state on a per module basis.
This allows for production ready and non-production ready plugins to
be identified.
Added function pointer array which is indexed by enumerated selection criterias.
Selection criteria can now be switched by modifying config file and reloading it.
The option is reloadable in the same way as max_slave_connections parameter. Option value determines which sort function is called before to sort backend server pointers before selecting them and establishing connections to backends.
Added missing makefile to server/modules/routing/test . It is needed for system testing. Prior this fix, 'make testall' failed because the makefile was missing.
In practice, 'reload config' reads config file and updates config parameters of rwsplit router service. In addition to that there is a version number indicating what generation of configuration service holds. When router instance is created (when MaxScale is started) service's config version is copied to router intance. Whenever new client connection (rwsplit session) is started, router instance's config version is checked against that of service's. If versions differ, service's config data is copied to router instance. New session will be started with router instance's config values.
query_classifier.cc use of uninitialized value in skygw_stmt_causes_implicit_commit
config.c crashed if module load failed, use of unitialized value
load_utils.c pretty-printed error
service.c use of uninitialized value in service_add_qualified_param
modules.h function prototype
readwritesplit.c memory leaks
1. in query_classifier.cc autocommit_enabled, and transaction_active variables maintained their values across different sessions. Now those values are stored in each router_client_ses object.
2. As a part of implementation of MAX-95 session variables were added to BACKEND struct which is shared with all sessions using the SERVICE which the particular BACKEND serves. Now each router_client_ses object has a backend reference struct which includes pointer to BACKEND, DCB and to session command cursor.
Added test - set_autocommit_disabled.sql, test_after_autocommit_disabled.sql - to check that session variable is discarded when session where it belongs terminates.
Parameter it read from config file to CONFIG_CONTEXT's parameter list. It is qualified in service.c:service_set_slave_conn_limit and if qualified, the qualified integer value and the value type are copied to the CONFIG_PARAMETER structure.
This CONFIG_PARAMETER struct is cloned (=copied to different memory area) and linked to RW Split SERVICE struct.
When RW Split router_instance is created in readwritesplit.c:createInstance, the value is copied to (new) rwsplit_config_t structure from SERVICE's parameter list.
When new routing session is created in readwritesplit.c:newSession, the rwsplit_config_t structure is copied to ROUTER_CLIENT_SES struct and the actual max_nslaves value is calculated from the config value (if percentage is used).
Tests and many error handling branches are missing but functionality seems to be working.
Increased skygw_query_type_t to 16 bits, and corrected the way how those bit fields are checked.
Added tests for cases where autocommit is disabled and corrected old tests.
